.exam_img1,.exam_img2,.exam_img3{width:684px;height:auto}.opt_div_box{background:url(./ai_icon1.Dsn5f9ki.png) 50%/100% 100% no-repeat;width:684px;height:371px;position:relative}.opt_div_box .opt_video{width:100%;height:100%!important}.opt_div_box .video_content{background:#231f20;width:470px;height:320px;position:absolute;top:2px;bottom:0;left:72px}